Genes expressed during the saprotrophic and the symbiotic phases in the ectomycorrhizal fungus Tuber borchii Vittal

Truffles are ascomycetes which live in symbiotic association with the roots of gymnosperms and angiosperms. Like other ectomycorrhizal fungi, they display a three stage-life cycle: a mycelial independent stage, a symbiotic mycorrhizal stage and a reproductive one leading to ascoma formation. In this study we characterized two EST (Expressed Sequence Tag) clones (VA48 and VA51), randomly isolated from T. borchii mycelium cDNA libraries, in order to investigate whether they are involved in the transition from the saprotrophic to symbiotic stage. VA48 clone (full length, 1158 bp), that does not show any significant similarity with known sequences, has been found to encode for a small rich-cystein protein (12 cys-residues) with a putative secretion peptide signal. VA51 cDNA fragment (643 pb) shows similarity to a ß-glucosidase gene ß-glucosidase 5, Coccidioides immitis), an enzyme that is implicated in cell wall catabolism and sugar metabolism. The gene expression has been studied in the mycelium and in the mycorrhiza of T. borchii by using RT-PCR experiments with specific primers designed on cDNA sequences. Mycelia were grown at different nutrient conditions and an in vitro ectomycorrhizal system between Cistus incanus and T. borchii has been developed. Preliminary results indicate that the EST clones are expressed in T. borchii during both mycelial and ectomycorrhizal stages. Semi-quantitative RT-PCR experiments will confirm whether the genes are differentially expressed under starvation conditions or during the different stages of the fungal life cycle. (Texte intégral)

Bibliographic Details

Main Authors:	Miozzi, Laura, Balestrini, Raffaella
Format:	conference_item biblioteca
Language:	fre
Published:	CIRAD
Subjects:	P34 - Biologie du sol, Mycorhizé, Tuber, gène, Tuber borchii, http://aims.fao.org/aos/agrovoc/c_5023, http://aims.fao.org/aos/agrovoc/c_7995, http://aims.fao.org/aos/agrovoc/c_3214, http://aims.fao.org/aos/agrovoc/c_fbf3a276,
Online Access:	http://agritrop.cirad.fr/490747/
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